Process of puring hard or vulcanized fiber.



cBiARLns ALMY, an, or WILMINGTON, nntawhnn asgm groa mo I E FIB OM ANY OF lmm li 'iiex etieae;

-T0' all whom; z't may concern Be it known" that I CHnRnEs ALL/13th., a citizen of the United States, residing at "Wilmington, in the. county of Newflastle and State of Delaware, have invented certain new'and useful Improvements in Processes Tof Puring Hard or Vulcanized Fiber, of which the following is a specification. -This invention relates to the manufacture of so-called hard or vulcanizedfiberand similar, products fandfparticularly to the socalled puring processes, the object vof theinvention being to provide a highly expedieconomical process of this charlose'paper, it is necessary to subject the product to a 'prolonged'puring or washing process for the removal of the excess of zinc 'chlorid. As heretofore usually practised, the -puring process involves subjecting the vulchlorid solution of progressively diminish- 'ing concentration, followed by. a plurality ofwashings with pure'water. The time required for puring dependslargely upon the canized fiber to a plurality of baths :of zinc thickness of'the laminated sheet, and in many cases approximates ten days for each one- --sixteenth inch inthickness; so that sheets having a thickness 'of three-eighths inch .may' require about two months for puring.

Accordingto the present process, thestime required for puring 'is greatly shortened,

especially in case ofthe thicker sheets.

I Careful analytical investigations 'loflthe removalof zinc chlor'idiby the puring process, as heretofore practised,"have shown that the elimination of zinc chlorid is at first quite rapid; becoming however "slower and slower as the treatment proceeds; and that the removal of-the final portions of the 'salt to Jattainthe "desired minimum percentage is extremely slow. For example, I have found that in the case of a sheet threeeighths inch in thickness, the percentage :of zinc chlorid,

based :upon the weight of dry fiberfwas reduced, in thirty days, from 130 per cent..to

cent; 3 1.

According to the present process, the hard or vulcanized-fiberbr similar material, prepared in any usual" or'desired manner, -and in the form of sheets, tubesor other articles, -1s subjected to the usualtreatment with zinc chlorid solutions of progressively diminish ing concentrationuntil the greater part of ficial-portionsof the sheet. (The sheet is then washed in pure water one or more times. By this treatment, a large proportion of the residual zinc. 1chl0ridis very quickly removed', and a product is obtained having the desired low percentage of the 'salt.- The saving of time thereby effected is in all cases material, andin the case of the heavier sheets may amount to many days.

' It istoibe understoodthat while I have referred specifically to zinc chlorid solutions,"

the process is directly applicable to other solutions" capable of giving similar results,

other than zinc salts.

- A'specific illustrative example of the new firemen e v I PBQG QF lU NGF H QQ 1.191.1 2. j s e e Jewels-. 6

No Drawing. Application filed March 19,1913 Seria1 NeI755A13. I i v i 1 about 1.!) per. cent and that it required some thirty days addltional' treatment to reach the esired ult mate percentage of- :02 to .O-Sper r as for example solutions. of other salts of Zinc, .or' solutions cfontainmg ingredients iprocessis as follows: A vulcanized fiber sheet .sevenreighths inch in 7 thickness in. the wet condition, was I-Washed as usual in zinc,

qchlorid solutions "of diminishing concentration until the. average chlorin content was content was reducedto approximately ten interior or central portions 9.201 per cent. of jchlorin: The-sheet was then washed with reduced to about {0.5 perl cent." of the mass.- 'iThQShBBt was then heated at a tem perature ,ofto 8. .G.., until its moisture-.

fro

soaking. a 7 1 1 i'lhe precise stage in the elimination of the zinechlorid at which the sheet is subjected tioned the following;

pure water at a temperature of to 0., when it was found that the zinc chlorid was very rapidly removed, and that two washingssufficed toreduce the percentage of zinc r fdi to e e ire mmerc al min m m- The process as above described may of course be modified as desired, according to the thick n'ess of the sheets or other articles 7 and the proportion of salt whichjis regarded as permissible in the final product. A complete drying of the'shee't, in the sense of expelling all moisture therefrom, preliminary! to the final Washing, is unnecessary and usuf ally undesirable. An evaporation .of as little 7:

as ten per cent. of the contained moisture showed, in certain cases, a markedieffect, but in most cases 1t ls'rpreferred t'o reduce the moisture-content toIlO to 25 "per cent. by weight of the fiber, as a preliminary toreto the above-described 'evaporative treat- .ment is not material to the invention, but

"it is preferred to introduce the evaporative treatment atsuch a point in the process that the concentration of the zinc chlorid in the interior oricentral portion of the isheetwill, after the evaporation, approximate the desired final concentration. If this is done, the final washing isfrequired torremove the zinc chloridfrom the surfaceand superficial portions of thesheet only, and

is therefore very quickly accomplished. 35,

Furthermore, the central portions of the sheet are not necessarily thoroughly soaked by the final washing, with the result that the final drying is expedited.

I The new process presents many material advantages, among which may be men- (1) A material saving of time in the final washing, and also in the final drying,'with the result ofexpediting the preparation of all sheets, and particularly the thicker grades. a

(2) In the finished sheets, as heretofore prepared, the percentage of zinc chlorid is invariably higher at the surface of the sheet than in its interior portions; whereas in sheets prepared according to the present process the surface-content of zinc chlorid is usually lower than the interior-content,

so that the proportion of zinc chlorid in the finished sheet usually diminishes from the center toward the surfaces.

This is a dis'tinguishing characteristic of sheets prepared according to the present process,and is distinctly advantageousas reducing the surfaceconductivity of the sheet, as well as its tendency to absorb moisture; from the 7 "air, as compared with a similar sheet prepared by the prior processes and having the same average-salt-cont'ent. .7

Ari illustrative example'of the composilwh'ich thearticle is subjectedlf tion of a sheet prepared according to the present invention is as follows:

i i/asked sheet threckfourfltsniwl thick.

Average chlorincontentill;;; r;; O. 116% Superficial chlorin-content 0.052% Central ichlorin-contentnn,1: 1; 0, 138% Finished sheet seven-sz'wteeath thick.

A era ealarm-content; 0.115% ,Superficial chlorin-content f 0. 069% Central chlorin -content 0.127%

is 'ofcbtis'etd be understood that this example is illustrative onlyfandf'that the percentages of salt may? bemade? either greater or less than those above mentioned,

according to; the details of thetreatment to (3) A material savingof 'zincchlorid or equivalent chemical'is efiected,fowing to the fact that the proportion of water. required :for the'final washing is so limitedas'to ren- 'der itpossible, in most, cases ,at least, l to return all -of the-resulting highly-"dilute salt solution to the process.

1 The process of puring hard or'vulcanized fiber and similar products, which consists in washing the same with suitable puring solutions of progressively diminishing concentration, subjecting the'fiber to an -evaporative process, and thereafter washing and drying the same. i"

2. The process of puring hard or vulcanized fiber and similar products, which consists in washing the. same withsuitable puring solutions of progressively diminishing concentratiom'then subjectingv the fiber 'to an evaporative'process to induce a move- 'ment of the residual salt to or-towardv the which consists in subjecting the fiber to an evaporative process to induce a. movement of the resldual'salt to or toward the surfaces thereof and to reduce the concentration of the salt in thecentral' portion toi-about the desired minimum, before the finalwashing.

5. In a process of puring hardnor vul- "canized fiber and similar products, by repeated washings, the step which "consists in sub ecting the fiber to an evaporative treatmentbefore the'finalwashinggl f" V 6. A sheet or other article of hard or proportion diminishing toward thesurfaces vulcanized fiber or like material characof the sheet. r 10 terized by the presence therein of the vul-' In testimony whereof I afi'ixmy signature canizing agent in proportion diminishing toin presence of two Witnesses; r 5 ward the surfaces of thesheet. I 7 CHARLES ALMY, JR.

7. A sheet or other article of hard. or Witnesses Y 7 vulcanized fiber or like material character- T. W. CAMPBELL, ized by the presence, therein of chlorin in V G. K. PARSONS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

V Washington, 1).,0. V r 

